CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Initial conditions = final conditions (http://www.cfd-online.com/Forums/cfx/21934-initial-conditions-final-conditions.html)

Chucho December 13, 2005 13:21

Initial conditions = final conditions
 
Does anybody knows how to set the results of a simulation as the initial conditions to a new simulation with CFX 5.7 or CFX 10?

Rajit December 14, 2005 00:30

Re: Initial conditions = final conditions
 
It is pretty simple.Use the .res file in the intial values file in the solver defintion form in the solver manager.

the first blank will be your new simulation file and the second blank will be the created res file.

then run this.it will take the intial values from the resolution file.

Thanks Rajit

TB December 14, 2005 03:58

Re: Initial conditions = final conditions
 
What I normally do is interpolate the old result file to new definition file. Look carefully on the menu bar in the solver manager. Of course you can use command line to do it. Refer to user manual.

Jeff December 15, 2005 12:00

Re: Initial conditions = final conditions
 
If the new run uses exactly the same grid, you can simply use the restart method Rajit gave you. Specify the old .res file as the initial values file. No need to interpolate, and I believe you get more information (i.e. control volume fluxes, etc.) than with interpolation which only interpolate the node values.

If the new run uses a refined mesh, but the same domain structure, you have to use interpolation to interpolate the old solution field onto the new mesh.

If the zonal structure has changed (new domains, or subdomains) then interpolation won't work either. I've been told by CFX that in this situation, you can write out the solution variables over the entire domain, and then do a cloud interpolation onto the new grid, but this requires user Fortran and is fairly complicated. It's never been worth the effort over just re-running the case on the new mesh.

Hope this helps. Jeff

Chucho December 15, 2005 20:15

Re: Initial conditions = final conditions
 
Tx for ur replies, but i'm having a problem. when i choose the .res file, the solver loads it but it only iterates for one more step, it doesn't simulates according to the finish time i set up. Also it removes previos steps from the res file when i open it with the post processor. Can u help me? Tx

Jeff December 16, 2005 18:14

Re: Initial conditions = final conditions
 
If it's a transient run, the current time will be picked up from the .res file. So if your simulation is set for 1000 seconds, and the .res file ran for 1000s, then only one time step will run as you've reached the time limit. Set the simulation time to 2000s for another 1000s of simulation.

The other possibility is that your residual targets are already reached using the initialization file. Set your residual targets lower.

Jeff


All times are GMT -4. The time now is 16:22.